A protein fat replacer is described in U.S. Pat. No. 4,734,287, to Singer, et al, and the present invention relates to an improvement therein. That Singer, et al patent describes, in detail, a proteinaceous, water-dispersible, fat replacer made of macrocolloidal particles of substantially non-aggregated denatured dairy whey protein. Since the description of that fat replacer is set forth in considerable detail in the Singer, et al patent, those descriptions will not be repeated herein, for the sake of conciseness, and the Singer, et al patent is referenced and relied upon herein for purposes of that disclosure.
Briefly, as set forth in the Singer, et al patent, heat denatured whey protein, having substantially non-aggregated particles with sizes of between about 0.1 and 2.0 microns, when hydrated, provide organoleptic properties which mimic fat/water emulsions, and, hence, may be used as a fat replacer in certain food compositions. That patent points out the theory by which the whey protein particles are produced, and according to that theory, whey protein, under denaturing conditions, undergoes first changes where the protein is denatured, and second changes where aggregated larger particles of the denatured protein are formed. The aggregated larger particles have particle sizes of about 15 to 175 microns, and particles of this size range do not have the fat mimicking organoleptic properties. According to the Singer, et al patent, by use of extremely high shear during the denaturing step, the larger aggregated particles are prevented from forming, and the resulting composition has, mainly, substantially non-aggregated denatured whey protein particles, i.e. particle sizes with a range of approximately 0.1 to 2.0 microns, which will provide the desired fat-mimicking organoleptic properties.
As characterized by the Singer, et al patent, the process produces novel whey proteins which are prepared by controlled or extent-limited heat denaturization under very high shear so as to prevent the formation of substantial amounts of large protein aggregates. In view of this method and the product which results therefrom, the Singer, et al patent also points out that in the event that the macrocolloid particles of the invention are, following their formation, subjected to additional denaturing temperatures or high heat treatments, the particles tend to form fused larger aggregates and hence lose the required organoleptic properties. Thus, the patent points out that the macrocolloid particles are heat labile and should be treated accordingly.
This disadvantage of the protein particles of the Singer, et al patent manifests itself when substantial amounts of those protein fat replacer particles are placed in food compositions which are intended to be heated, as opposed to those food compositions which are not intended to be heated. For example, this heat labile property of the Singer, et al particles may not be apparent in foods such as ice cream, and other frozen desserts, since limited heat treatment of the heat labile particles is practical, e.g. as low temperature-long time pasteurization. On the other hand, if those fat replacer particles are placed in food compositions which are intended to be heated to substantial high temperatures, e.g. above about 160.degree. F., that heat labile property is very strikingly exhibited. For example, if the Singer, et al particles are used in sauce compositions, when the sauce composition is heated, e.g. a gravy heated on a steam table, for some period of time, the gravy forms a soft gel. In addition, the Singer, et al protein particles further aggregate, as acknowledged in the Singer, et al patent, and these larger aggregates not only lose the fat mimicking properties, but produce an unappetizing form of the sauce, e.g. gravy. In low viscosity compositions, e.g. a heated beverage, very noticeable sediments occur. Under the circumstances, the Singer, et al fat replacer particles cannot be effectively used in food compositions which are intended to be given significant higher temperature heat treatments, such as ultra high temperature retorting and high temperature-short time pasteurization, and to a lesser extent with low temperature-long time pasteurization, and, thus, the use of those fat replacer particles is severely limited for general food use.
It would, of course, be of considerable advantage to the art to provide fat replacer particles, similar to those of the Singer, et al particles, and which exhibit the required organoleptic properties, but which are not so heat labile and which do not, concomitantly, exhibit such instability. It would further be of advantage to the art to provide such fat replacer particles which can be manufactured in a more efficient, inexpensive and straight forward method than the high shear method required for manufacture of the Singer, et al particles. It would be a further advantage to the art to provide similar fat replacer particles where those particles could be processed according to usual dairy processes, e.g. continuous high temperature-short time (HTST) pasteurization as opposed to batch low temperature-long time (LTLT) pasteurization, without degradation of the organoleptic or stability properties. It would be a further advantage to practice such an improved process with generally available whey protein, rather than the special whey protein of the Singer, et al patent, and to provide a spray-dried form of the fat replacers. Further, it would be of advantage to provide such fat replacers which are easy to rehydrate without high shear to organoleptic sizes of particles.